Separation of composite particles made up of magnetite carrier particles and adsorbed flakes of calcium phosphate and calcium carbonate is known from the article "Magnetic separation in water pollution control", IEEE Transactions on Magnetics, vol. 11, No. 5, September 1975.
According to this known method an ultrasonic field is applied to the fluid, and the separation of composite particles into magnetite particles and the flakes takes place slowly, so the separation process takes excessive time.
Further, the achieved separation is not complete. Unseparated composite particles and flakes remain.
The aim of the present invention is to provide a method for separating such composite particles, in which the separation process can take place in a shorter duration of time, and in which a more complete separation is achieved. This aim is reached in that the particles together with the flakes adhered thereto are subjected to a substantial velocity gradient. By the velocity gradient the particles are subjected to shearing forces, which cause an effective separation of the composite particles into elements.